FontLab 5: Different ClearType hinting preview in Windows 10

It’s becoming increasingly difficult to proof pure ClearType GDI rendering. Browsers now use DirectWrite, which cannot be deactivated anymore (the config switches in Chrome and FF are gone). And now I noticed that the ClearType hinting preview in FontLab 5 has changed since I installed the Windows 10 Creators Update. The hinting preview now uses ClearType with vertical smoothing.

If you look closely, you can see the ‘e’, in which I removed the stem assignments, the horizontal parts look slightly fuzzy. Also, the typical CT staircases are missing from the other letters.

Who would have thought that the old FontLab would get a rendering update?

for the best rendering, when y-axis anti-aliasing kicks in, as well as keeping older GDI looking good

to proof in FontLab on the Creators update to simulate older GDI, you could set the GASP table, in the font, temporarily, to disable y-smoothing until a larger size. this would however just be a proofing method and would need to be set correctly for all rendering environments, before shipping.